WIP attr macro (#316)

* some progress on attribute macro

* first draft, tests still broken

* nix cleanup

* use real trybuild

* test for config parameter

* PR feedback - use formatted Display impl for snapshot test

* add hygiene test

* PR feedback

* pin to trybuild 1.0.0 for MSRV

* actually pin properly

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -9,3 +9,5 @@ persistence-test.txt
 
 # IntelliJ
 .idea
+
+/.direnv

Cargo.toml

@@ -3,6 +3,7 @@ members = [
     "proptest",
     "proptest-derive",
     "proptest-state-machine",
+    "proptest-macro",
 ]
 
 exclude = ["proptest/test-persistence-location/*"]

flake.nix

@@ -0,0 +1,32 @@
+{
+  description = "proptest development environment";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
+    flake-utils.lib.eachDefaultSystem
+      (
+        system:
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ (import rust-overlay) ];
+          };
+        in
+        {
+          devShells.default = pkgs.mkShell {
+            nativeBuildInputs = with pkgs; [
+              rust-bin.nightly.latest.default
+
+              cargo-insta
+            ];
+
+            TRYBUILD_CARGO_CMD = "test";
+          };
+        }
+      );
+}

proptest-derive/src/ast.rs

@@ -14,7 +14,6 @@ use std::ops::{Add, AddAssign};
 
 use proc_macro2::{Span, TokenStream};
 use quote::{ToTokens, TokenStreamExt};
-use syn;
 use syn::spanned::Spanned;
 
 use crate::error::{Ctx, DeriveResult};

proptest-macro/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "proptest-macro"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+syn = { version = "2", features = ["full"] }
+quote = "1"
+proc-macro2 = "1"
+convert_case = "0.6"
+
+[dev-dependencies]
+insta = "1"
+prettyplease = "0.2"

proptest-macro/src/lib.rs

@@ -0,0 +1,8 @@
+use proc_macro::TokenStream;
+
+mod property_test;
+
+#[proc_macro_attribute]
+pub fn property_test(attr: TokenStream, item: TokenStream) -> TokenStream {
+    property_test::property_test(attr.into(), item.into()).into()
+}